New to this wonderful forum, for years I was looking for a nice Philco TV set, and finally my sturdiness pays off, I found one locally (Bogota-Colombia) in mint condition including the little table, my technician restored it and love it. My question is how often should I turn it on and for how long??

Tough question. The biggest thing is the condition of the picture tube. If it is weak and you don't have a spare you might want to view it very occasionally. Or perhaps you are the type that would rather enjoy it while you can. In my case, I have a NOS picture tube and an OK spare, so I watch when I like, usually once a week for a few hours.

In general, these sets were run for hours a day, every day. So they were made to take some hours. I'm a "smoke 'em if ya got 'em" kinda guy and the Princess isn't a particularly rare set. Also, if you keep the brightness down and watch in a dark room it will last longer.